What constitutes diligence in raising newly discovered medical and/or mental health evidence and diagnoses?

QUESTIONS PRESENTED This Court established long ago that the Eighth Amendment “requires consideration of the character and record of the individual offender and the circumstances of the particular offense as a constitutionally indispensable part of the process of inflicting the penalty of death.” See, e.g., Woodson v. North Carolina, 428 U.S. 280, 304 (1976). Given the realities of the modern death penalty, however, many prisoners remain on death row for decades before their execution. This has led to a complicated question for lower courts dealing with post-conviction claims based on ever-evolving medical and mental health science: whether to consider legitimate posttrial evidence speaking directly to a prisoner’s appropriateness for a death sentence. The result is that jurisdictions are imposing markedly different diligence standards on death-sentenced individuals and defense counsel advancing claims relying on new medical diagnoses. The questions presented are: 1) What constitutes diligence in raising newly discovered medical and/or mental health evidence and diagnoses? 2) Are capital defendants confined to the medical and mental health science available at the time of their trial, or must the lower courts provide a meaningful opportunity for advancements in scientific evidence to be heard? i